J. D. Dana’s Mineralogical Contributions. 79 
ing with the habits of the species. Moreover, another method of 
tabulating the planes may accomplish the same result more simply, 
we think, and one in. which the planes shall be indicated by their 
true expressions, instead of arbitrary letters. The method allu- 
ded to, has already been presented in this Journal, in the writer’s 
paper on Sphene and Euclase. It contrasts with the method in 
Brooke and Miller’s‘work mainly as Mercator’s projection of a 
sphere contrasts with the spherical projection. 
The method of calculation adopted, is based for the most parton 
spherical trigonometry. It is less general in its formulas and less 
elegant, we think, than the system from analytical geometry, but 
sometimes affords more concise equations. The hexagonal sys- 
tem is rather at variance with itself in the method used. ‘The 
planes are referred to three axes,—the three lines that connect the 
centres of opposite faces in a rhombohedron. The plan is not 
onal system. But in the hexagonal section of this system, in 
must have different mathematical expressions. This leads the 
mathematician to no error; but tends to perplex a simple subject 
for the student. 
But these are minor points, and leave the work still, the most 
accurate, thorough, and original work on the crystallization of 
minerals that has been published. 
2. Von Kobell’s “ Mineral-Namen.”* 
mology. He presents, First, a catalogue of those names that are 
. of mythological origin. Second, leaving the gods and mythology, 
he passes to those derived from the names of cultivators of the 
science, collectors of specimens, patrons, statesmen, and what not, 
among whom, about two hundred and thirty are hereby com- 
eral species are subject and the custom of change in authors, very 
many of the names are already in the rubbish heaps of the science. 
Third, comes a list of the names derived from localities ; fourth, 
those alluding to the structure of the species; fifth, those based 
* Die Mineral-Namen tmd die mineralogische Nomenklatur, von Franz von Kobell. 
162 pp. 8vo; Miinchen, 1853. Briefly mentioned in this Journal, page 304, vol. xvi, 
